Improvements in topping-up devices for electric batteries



United States Patent Inventors Patrick Ewart McKellen;

IMPROVEMENTS IN TOPPING-UP DEVICES FOR ELECTRIC BATTERIES 13 Claims, 5 Drawing Figs.

US. Cl 141/198, 136/162, 137/260 Int. Cl. H0lm 7/00 Field of Search 136/162,

[56] References Cited UNITED STATES PATENTS 678,324 7/1901 Waterhouse 137/428X 1,285,658 11/1918 Ford 136/162.4UI"I 2,618,237 11/1952 McDermott et a1. ll9/78U'X 3,189,063 6/1965 Lowe 136/162X FOREIGN PATENTS 663,870 5/1964 Italy 136/162 821,647 8/1937 France 119/78 Primary Examiner-Fred C. Mattem, .lr. Assistant Examiner-Edward J. Earls Attorney-Watson, Cole, Grindle and Watson ABSTRACT: A topping-up device for electric batteries comprises an inlet chamber above the battery, communicating via a liquid trap with a filling passage leading into an airlock compartment in the battery in which a pressure head builds up when the liquid rises above a desired level, so causing the level to rise in the inlet compartment. A float-controlled valve is mounted in the inlet chamber to control the admission of 457 further liquid to it.

PATENTED UEB29 I970 SHEET 2 UF 2 INVLNTORS PATRICK EWART mcKeLLEN DENNIS ALBERT Cuwwou IMPROVEMENTS IN TOPPING-UP DEVICES FOR ELECTRIC BATTERIES This invention relates to topping-up devices for topping up electric storage batteries with liquid to a desired level.

The invention is concerned with devices of the type including a partition dividing the space in the container above the desired liquid level into two compartments, one of which, the vented compartment, is provided with a vent passage to allow air to escape, while the other, the airlock compartment, is connected to an inlet chamber for liquid situated above it through a filling passage which includes a liquid trap including a wier over which liquid flows into the airlock compartment, so that when the liquid surface rises above the effective level of the bottom of the partition it prevents further escape of air from the airlock compartment and builds up a pressure head therein to prevent entry of further liquid through the filling passage. l

lt will be appreciated that in such a filling device if the head of liquid in the inlet chamber is increased the level to which the container will be'filled will be correspondingly increased. For example, in the case of a multicell electric battery provided with a topping-up system in which the inlet chambers of different cells are connected to a common filling manifold, difficulty may be experienced in filling the cell furthest from the supply without building up a pressure head in the inlet chamber of a cell near to the supply, and thereby overfilling the latter cell. Similarly, if the battery is not quite level the head of liquid in the inlet chamber of a lower cell will be greater than that in the inlet chamber of a higher cell. The invention is particularly applicable to traction batteries, and other applications in which topping-up is done regularly, and perhaps automatically, and over-filling could be cumulative.

An object of the present invention is to overcome these disadvantages.

According to the present invention the filling device is provided with means responsive to the liquid level in the inlet chamber for preventing admission of further liquid to the chamber from a supply when the liquid in the chamber rises above a predetermined level. Such means conveniently take the form of a float-controlled valve. Preferably the upper edge of the weir lies above the level of the bottom of the float.

The float may itself form part of the liquid trap. The weir may be of annular form, while at least part of the float is of annular form surrounding it. Thus the inlet chamber may have the filling passage projecting up through its bottom and an inlet passage opening through its top coaxially, while the float affords or carries means to close the inlet passage, and a depending annular skirt encircling the top of the filling passage.

The skirt may be afforded by a buoyant ring such as a closed annular chamber. Alternatively, the skirt may comprise a single solid wall, of metal or plastic, the float being of diving bell type whereof the buoyancy results from the air trapped within The inlet chamber is preferably provided with an overflow opening or passage so that even if the valve should fail to close (for example due to dirt or vibration) the head applied to the liquid trap can not exceed a certain maximum.

in one form the invention is a modification or improvement of that disclosed in British Pat. No. 1,142,0l0. Thus as set forth in that specification'the partition may take the form of an airlock conduit arranged to extend down into the container to a point in the region of the desired level and to enclose an airlock compartment of such cross section as to allow liquid to flow down past the air in it.

Alternatively or in addition the partition may be such that the joints between the walls and the lid of the container, and preferably also between the lid and the terminal posts, are in the vented compartment.

Such an arrangement, as discussed in the patent referred to, has the advantage that the action of the filling device does not depend on the container being completely airtight (as has been the case with certain known devices). The places where leakage is most likely to develop after prolonged use are generally the joints between the lid and the walls of the container and between the lid and the terminal posts. Thus the lower part of the airlock conduit may be constituted by a partition to fonn an enlarged airlock compartment, provided these joints remain outside it in the vented part of the cell container.

The partition may enclose the major part of the liquid surface and may depend from and be formed integrally with the lid.

In an alternative form of the invention the device is formed for removable insertion through a filling opening in the top of the container, and the airlock conduit is of sufficiently small cross section to pass through the opening. Thus in the case of a battery the device may be formed to replace the ordinary filling and vent plug.

The inlet chamber is preferably situated above the battery lid.

The invention may be put into practice in various ways but certain specific embodiments will be described by way of example with reference to the accompanying diagrammatic drawings in which:

FIG. 1 is a sectional elevation of one form of filling device for topping up an electric storage battery and,

FIGS. 2 to 5 are views similar to parts of FIG. 1 showing modified arrangements.

In one embodiment shown in FIG. 1, for topping-up an electric battery in which eachcell 10 has a separate lid 11 with an opening 12 for a vent plug, each of the vent plugs is replaced by a filling device in accordance with the present invention.

The filling device has a lower tubular portion affording an airlock conduit 15 of such length as to extend down into the cell to a point just below the desired liquid level. The airlock conduit is of substantially the full cross section of the vent plug hole so that liquid can flow down past the air in it.

Supported on the top of the airlock conduit is a cylindrical inlet chamber 16 of larger diameter than the airlock conduit. The external walls of the airlock conduit are provided with screw threads or bayonet lugs 17 to secure the device in the vent plug hole, a washer 18 being inserted between the top of the latter and the lower face of the inlet chamber.

A filling passage 20 projects upwards into the inlet chamber from a central hole in the bottom of the latter and is provided with a cap 21, the cap comprising a disc with a depending skirt encircling the top of the filling passage to afford a liquid trap.

The annular space surrounding the filling passage and its cap is occupied by an annular float 22 controlling a valve 23. The valve conveniently comprises an inlet passage 24 projecting centrally through the top of the inlet chamber and cooperating with a disc 25 forming the top of the float and provided with a washer of soft rubber or other suitable material to close the inlet passage when the float rises in the inlet chamber. The part of the cell outside the air lock conduit is vented through a suitable vent opening 26.

The inlet passages 24 of a group of cells are connected together and to a supply of liquid by a series of pipes 27 forming a manifold. Accordingly in operation liquid is supplied to the manifold and flows through the inlet passage of each cell into the inlet chamber, whence it passes-through the liquid trap 20, 21 and down through the airlock conduit 15. When the level of liquid in the cell reaches the bottom of the airlock conduit, which forms a partition between the airlock compartment within it and the vented compartment outside it, air can no longer escape from the airlock conduit and accordingly the liquid rises in the vented compartment and builds up a pressure in the airlock conduit. Thus, further liquid can only pass through the liquid trap and filling passage if the level of liquid in the inlet chamber rises to a corresponding extent. As it does so the float 22 in the inlet chamber rises so as to close the lower end of the inlet passage 24. The effective area of the float is very much greater than that of the lower end of the inlet passage so that the supply of liquid to the inlet chamber will be cut off even though there is an appreciable head of liquid in the inlet passage.

Accordingly the arrangement will operate satisfactorily to fill the cells equally, even though the length of the manifold connecting one cell to the supply may be very much greater than that connecting another cell to the supply. In addition the arrangement will operate satisfactorily even if the cells are at different levels, for example if a vehicle in which they are fitted is not on a level surface. Moreover satisfactory operation does not necessitate the provision of manifold pipes of unduly large diameter. As compared with certain known arrangements relying entirely on a float-controlled valve, the arrangement has the great advantage that the float can remain outside the battery. It therefore lends itself to a device replacing the usual filling and vent plug, and can have a float chamber of such size that it could not pass through an existing filling plug opening, or one of reasonable size. Moreover the float is only exposed to pure water and not electrolyte.

The inlet chamber is provided near the top with an overflow opening or passage 28. This may be merely a spill hole discharging on to the top of the cell, since it will only function if the valve should fail to close, and then will only discharge pure water. Alternatively the overflow openings may be connected by pipes to waste.

FIG. 2 shows a further arrangement in which the partition separating the airlock compartment from the vented compartment, instead of being formed as part of the device that is screwed into the vent plug hole, is formed as a depending skirt formed integrally with the lid of the cell. In this case it may be designed so that the airlock compartment constitutes the major part of the area of the cell, the vented compartment including the joints between the lid and the container and the joints between the lid and the terminal posts, and little more. This arrangement has the advantage that a small addition of liquid to the cell will produce a relatively large rise of pressure and hence head of liquid in the inlet chamber. It also avoids the need for a rather large vent plug and filling hole 12. In other respects the arrangement may be as shown in FIG. 1.

FIG. 3 shows a further embodiment in which a float itself forms part of the liquid trap. This arrangement is very similar to that of FIG. 1 except that the cap 21 of the filling passage 20 is omitted. The float then comprises a disc forming its top and a depending annular buoyant skirt encircling the upstanding filling tube with which it forms the liquid trap in addition to acting as a float.

In either of the forms described the skirt of the float may be of hollow or other buoyant form. This, however, is not necessary and in a further arrangement shown in FIG. 4 a float is in the form of a simple cap or bell comprising a metal disc with a single-walled skirt depending from its periphery. Such a float possesses buoyancy in the manner of a diving bell due to the fact that the pressure of the air in the filling passage acting upwards on the underside of its top wall is greater than the pressure in the inlet chamber acting downwards on that wall.

In each of the constructions described, the float, and the cap of the filling tube, if any, may be provided with radial fins to guide the float.

The form of the valve may vary, for example the float may carry a hemispherical poppet 41 as shown in FIG. 3 or a conical poppet 46 as shown in FIG. 4 adapted to close the lower end of the inlet passage irrespective of slight tilting of the float.

In addition various arrangements may be employed for venting the vented compartment. Thus the lid of the cell may be provided with one or more venting openings 26 or passages at any convenient positions. Alternatively where the partition is afforded by an airlock conduit integral with the removable filling device the vent passage may be incorporated in the device. Thus in one arrangement one or more vent pipes extend up through the peripheral portion of the inlet chamber from a point outside the airlock conduit and either open to atmosphere or open into the upper part of the inlet chamber which is in turn vented to atmosphere through a spill hole.

In a further arrangement shown in FIG. 5 an L-shaped vent pipe 51 extends radially inwards from a hole in the airlock conduit and then vertically. upwards coaxially with the device, through the filling tube. The airlock may be formed by a cup 52 with the vent tube extending through and secured to its bottom, and a skirt 53 depending into the cup from annular disc 54 secured to the top of the filling tube 20. The float 55 in this case is provided witha chimney or dome 56 surrounding the upper part of the vent pipe and having lateral openings 57 into the upper part of the inlet chamber: The top of the dome or chimney then forms or carries the valve member for closing the inlet passage.

It will be appreciated that various forms of supply manifold may be employed. Thus an open ended manifold may be used communicating at one end with the supply and at the other end with a drain. In general, however, it will be preferred to employ a closed manifold communicating only with a supply of topping up liquid.

We claim:

1. A filling device for topping-up battery cells from a liquid supply to a desired level, comprising:

a partition for dividing the battery container into a vented compartment having an air vent passage and an air lock compartment extending downwardly to the electrolyte;

a liquid inlet chamber having a bottom surface and mounted to said container above said air lock compartment;

a filling passage connecting said inlet chamber and air lock, said filling passage including means for trapping liquid, said means for trapping liquid including a weir extending above the bottom surface of said inlet chamber over which liquid flows into said filling passage;

said inlet chamber including means responsive to the liquid level in said inlet chamber to prevent admission of additional liquid to the chamber from said supply over a predetermined liquid level in said chamber established by said weir and said means responsive to the liquid level; and

said air lock compartment preventing escape of air therefrom to build up a pressure head to prevent entry of liquid through said filling passage.

2. A device as claimed in claim 1 in which the means responsive to the liquid level comprise a float controlled valve.

3. A device as claimed in claim 2 in which the upper edge of the weir lies above the level of the bottom of the float.

4. A device as claimed in claim 2 in which the float itself forms part of the means for trapping liquid.

5. A device as claimed in claim 4 in which the weir is of annular form and at least part of the float is of annular form surrounding it.

6. A device as claimed in claim 5 in which the filling passage projects through the bottom of the inlet chamber and said inlet chamber includes an inlet passage opening through its top coaxially with said filling passage, said float carries means to close the inlet passage and a depending annular skirt encircling the top of the filling passage.

7. A device as claimed in claim 6 in which the skirt is a buoyant ring.

8. A device as claimed in claim 6 in which the skirt comprises a single solid wall, the float being of the diving bell type whereof the buoyancy results from the air trapped within it.

9. A device as claimed in claim 2 in which the inlet chamber includes an overflow opening for limiting the pressure head applied to the liquid trap.

10. A device as claimed in claim 1 in which the partition forms an airlock conduit extending into the container to a point in the region of the desired level and said airlock compartment is enclosed by said partition and is of such cross section to allow liquid to flow down past the air in it.

11. A device as claimed in claim 10 in which the partition encloses the major part of the liquid surface.

12. A device as claimed in claim 10 wherein said battery container includes a battery lid and said partition depends from and is formed integrally with said battery lid.

13. A device as claimed in claim 1 in which the inlet chamber is situated above the level of the battery lid.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N Dated 29 Patrick Ewart McKellen; Dennis Albert Clayton Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading, after "Great Britain 7727/66" please insert --fi1ed October 2, 1966--.

Signed and sealed this 13th day of July 1971.

(SEAL) Atteet:

EDWARD MEIETCHERJ'R. WILLIAM E. SCHUYLER, JR. Atteeting Officer Commissioner of Patents 

